Which roof-mounted vertical antenna (high antenna) with radials is recommended?

The optimal vertical radial antenna for use at high altitudes depends on various factors such as the desired operating frequency, space conditions and the specific area of ​​application. In general, a quarter wavelength vertical antenna should be sized for the desired frequency to achieve a good radiation pattern and low input impedance. When installing at high altitude, it is important that the antenna is equipped with a sufficient number of radials, which are positioned horizontally or sloping slightly downwards away from the base of the antenna in order to simulate the grounding conditions and to form an efficient counterpole to the radiation surface. The quality of the material, protection against the elements and mechanical stability are also important to ensure long life and reliable performance in various environmental conditions. The popular half-wave antennas also work well without large radials, but usually have a more upward radiation.